Yukon researchers use silicone oil to transport and preserve permafrost samples
Joel Krahn/Yukon News
Core samples of Yukon permafrost are on a 5,000-kilometre journey to Ottawa to be part of a permanent museum exhibit on the Arctic.
The two samples are believed to be the first permafrost cores to ever be put on display publicly in a museum.
Last year the Canadian Museum of Nature announced plans to open a new 8,000-square-foot Arctic gallery taking up the top floor of the museum in downtown Ottawa.
A small glass freezer is being built to store samples as part of a section of the museum that focuses on the Arctic climate.
The display with the cores will include information on permafrost and what happens when it melts, said Caroline Lanthier, the gallery’s senior content developer.
“A picture is worth a thousand words but now it’s the thing itself so it’s even better than a picture.”
Storing permafrost is not as simple as making room in your standard grocer’s ice cream display case. But two scientists at the Yukon Research Centre have come up with a way to preserve the cores for others to enjoy indefinitely.
During the summer, Yukon researchers drill burr holes and take permafrost samples from the ground.
They slice the samples in half to get a clear picture of the layers of ice and sediment that are supposed to stay frozen year round.
Melting permafrost in the North has been blamed for phenomena ranging from the changing chemistry of the Yukon River to structural issues at the Ross River School.
The research centre stores most of its samples in plastic bags in a walk-in freezer. Over time the exposure to air causes the samples to degrade.
That’s particularly problematic when the cores are sliced open and the centre, where the layers of sediment and ice are most visible, is exposed.
Joel Krahn/Yukon News
“We wanted to be able to keep it for longer,” said Fabrice Calmels, a permafrost researcher.
In a three-year-old sample that came out of a chest freezer, grooves in the dirt that used to be full of ice are clearly visible. Eventually that sample will be reduced to just dirt.
The lifespan of a permafrost core varies depending on the amount of ice, said analyst Louis-Philippe Roy.
After some testing, Roy and Calmels realized that storing the cores in clear cylindrical tubes filled with cooled silicone oil was the best way to preserve them.
The oil has a much lower freezing point than water, meaning it can get cold enough to keep the permafrost frozen but not freeze solid or damage the sample. It preserves the core and helps magnify it.
The pair had been working on an idea to preserve the cores before they were approached by the museum. They want samples to be available to researchers, students and the public.
“You step on (the ground), you see the degradation (of permafrost), the results,” said Calmels. “But even for northerners, not everyone has ever seen it.”
Roy said having preserved samples could be helpful in universities.
“As a student I would have loved to see that. When I was studying, it took years until I came to the North and actually saw it.”
There’s also the fact that permafrost is disappearing. At this rate, the preserved samples could be all that’s left of some permafrost.
Researchers are working at a site close to Jean Marie River in the Northwest Territories where the permafrost is disappearing at a much faster rate than other areas, Calmels said.
“It’s true that some of the cores that we have (preserved) here might still be here in the same condition in 10 years but the site where we collected the cores won’t exist anymore.”
The research centre lab has a display freezer of its own containing 10 permafrost core samples from Alaska and the Dempster Highway, Old Crow and Jean Marie River.
Not every sample that is collected will be preserved in oil — only the ones that are particularly valuable for research.
The two samples going to Ottawa represent two types of permafrost that are common in the Yukon.
The first, taken near the Canada/U.S. border north of Beaver Creek, is wedge-style permafrost formed when water freezes in cracks in the ground. The second, taken about 30 kilometres from Burwash Landing, shows layers of ice formed between bits of sediment.
“They were impressive and they were aesthetically nice to look at,” Roy said.
Last month, Roy brought the samples to the museum’s collections facility in Gatineau, Que.
They will remain in storage there until the new gallery opens in June 2017.
Getting a chance to look at a sample up close makes it easier for people to make connections between permafrost and what happens when it melts, Calmels said.
“You have the bumps along the Alaska Highway, you have the Ross River School that is collapsing, that’s because of that,” he said. “It’s a direct consequence of the degradation of the core that you’re looking at.”